Purpose
Include a user function in a nonlinear constraint.
Synopsis
function F(UF:userfunc, arg:linctr):nlctr
function F(UF:userfunc, arg:nlctr) :nlctr
function F(UF:userfunc, arg:list of nlctr) :nlctr
function F(UF:userfunc, arg:array(any sets) of nlctr) :nlctr
function F(UF: userfunc, arg:list of nlctr, returnarg: integer) :nlctr
function F(UF:userfunc, arg:array(any sets) of nlctr, returnarg:integer) :nlctr
Arguments
UF

A user function of type userfunc

arg

Argument to be passed to the user function

returnarg

Return argument to be substituted into the formula for multivalued user functions

Return value
A nonlinear expression which may form part of any nlctr.
Example
The following example shows how to implement a negative cosine function.
model "SimpleUF"
uses "mmxnlp"
declarations
obj: nlctr
x: mpvar
MinusSine : userfunc
enddeclarations
! creation and assignement of the user function
MinusSine := userfuncMosel("MinusSineImplementation")
! which can then be embedded into any nonlinear expression
obj := F(MinusSine,x)
minimize(obj)
function MinusSineImplementation (x:real) : real
returned := sin(x)
endfunction
endmodel
Further information
User functions allow extremely complex, recursive or nonalgebraic expressions to be included in nonlinear formulae.
As such they may make use of simulators or other black box evaluators. The actual parameters to a user function depend
upon the way it is bound to the model by the
F function. Please see the chapter on user functions for more details.
Each user function instance defined by the means of the F function must share the same argument syntax structure, however
the actual formula content may differ: e.g. if
a function takes an array of nonlinear expressions as input arguments, each instance of the function corresponding to the
same definition based on the same F instance must
have the same underlying array structure, although the expressions stored in them may differ. If a separate F instance is
used using the same function implementation, this rule
does not apply. Also note, that for Mosel to be able to correctly cross reference the sets used in the definition of an array,
the sets must be named.
Related topics
Module
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